Numerical simulation of flow dynamics in a tidal river under various upstream hydrologic conditions

Abstract

A three-dimensional Environmental Fluid Dynamics Code model was developed for a 17-km segment of the Mobile River, Alabama, USA. The model external forcing factors include river inflows from upstream, tides from downstream, and atmospheric conditions. The model was calibrated against measured water levels, velocities, and temperatures from 26 April to 29 August 2011. The Nash-Sutcliffe coefficients for water levels were greater than 0.94 and for water temperatures ranged from 0.88 to 0.99. The calibrated model was extended approximately 13 km upstream for simulating unsteady flow, dye, and temperature distributions in the Mobile River under different upstream inflows and downstream harmonic tides. Velocity profiles and distributions of flow, dye, and temperature at various locations were analyzed and show that flow recirculation could only occur under small inflow (50 m 3 s-1) when downstream tides control the flow pattern in the Mobile River. The model results reveal complex interactions among discharges from a power plant, inflows, and tides.

Hydrodynamic Modeling and Simulation of Water Residence Time in the Estuary of the Lower Amazon River

“…These results allowed concluding that the simulated water mass exchange in the study site was coherent with a plausible behavioral pattern. They presented approximately the same order of magnitude when they were compared to similar studies about the application of modeling processes in estuarine systems under tidal influence [64,[66][67][68][69][70].…”

“…Classical tests were adopted to quantify the efficiency of mathematical models: Nash-Sutcliffe Efficiency (NSE) (Equation (5)), Person's correlation, r 2 and Index of Agreement (d) (Equation (6)). These tests were selected given their different practical applications in hydrodynamic modeling for water studies, i.e., to test the accuracy and capacity of the models to represent the physical reality [65][66][67][68].…”

Understanding flow dynamics and density currents in a river-reservoir system under upstream reservoir releases

“…To more accurately simulate complex flow and temperature distributions in BRRS, especially near the power plant, the 3D EFDC hydrodynamic model was applied for the project to understand the hydrodynamics of density currents formed by upstream reservoir releases. The EFDC model is a general purpose modeling package that can be configured to simulate 1D, 2D, and 3D flow, transport and biogeochemical processes in various surface water systems including rivers, lakes, estuaries, reservoirs, wetlands and coastal regions (Shen and Lin 2006, Çalışkan and Elçi 2009, Jeong et al 2010, Wang et al 2010, Kim and Park 2012, Devkota and Fang 2015. The EFDC model was originally developed at the Virginia Institute of Marine Science and the version of EFDC used for the study with pre-and post-processing tools was EFDC-DSI (Craig 2010) from the Dynamic Solutions-International, LLC (http://efdc-explorer.com/).…”

Flood hazard mapping and assessment in data-scarce Nyaungdon area, Myanmar

“…The river routing equations (width (m) = 5.0A 0.35 , depth (m) = 0.95A 0.2 ) are used as default settings for deriving river channel widths and depths, where A is the upstream contributing area in km 2 (Eqs 1 and 2). The channel geometry is assumed as a rectangle in the model in which the river width, depth, and embankment height were considered [27, 30]. In this study, the assumption of the river width is based on Google Earth images [27, 31] and the depth on the local survey data of the Department of Meteorology and Hydrology for Ayeyarwady River.…”